1. Field of the Invention
The invention relates to an air-bag device which can be inflated as a protective wall in front of a vehicle side wall.
2. Discussion of the Prior Art
A known air-bag device of the generic type (DE 296 10 920 U1; WO 96/26087) can be inflated as a protective wall in front of a vehicle side wall having vertical pillars. For this purpose, the air-bag device includes a gas generator having fillable restraint cushions which, in the folded-up inoperative state, are concealed under a paneling part of a lateral roof longitudinal member. In the event of a side impact, the gas generator is activated by means of an impact sensor. The restraint cushions are filled by means of a gas mass flow and moved into a restraint position in which they cover the upper region of the side window of the vehicle wall. In this arrangement, the restraint cushions are connected to one another to form a restraint mat which remains secured essentially along its entire longitudinal extent in the region of the lateral roof longitudinal member. The filling procedure of the restraint cushions takes place via a filling pipe in the form of a metal pipe having outlet openings offset over the length. The filling pipe likewise extends along the entire longitudinal extent in the region of the lateral roof longitudinal member and is connected to the gas generator. Filling pipes of this type as gas lances made of metal or plastic have the disadvantage of a relatively large overall volume and heavy weight.
A protective wall of this type is used in particular as a side airbag for the head in order to dampen a head impact of an occupant in the event of a side impact and/or overturning. The intention is furthermore thereby to prevent particles, for example of destroyed side windows, paneling parts etc., from flying into the occupants compartment.
On account of the occupants head not being very far from vehicle side parts, it is precisely inside air-bag devices that very rapid inflating procedures of the restraint cushions are required in order to still bring the latter in front of the vehicle side parts before a head impact. In spite of the high filling speeds achieved up to now, further improvements are desirable here. One problem of the air-bag devices resides generally in the aggressiveness shown with respect to occupants, which can occur, in particular if an occupant is xe2x80x9cout of positionxe2x80x9d (OOP).
In a similar known air-bag device (DE 196 47 679 A1) a mat consisting of pneumatically connected beads is inflated as the protective wall in such a manner that a gas generator is connected at one location on the mat and a gas mass flow is blown in. A filling pipe in the form of a gas lance inserted into the mat is not provided here. Because the filling takes place only via one location without additional filling or unfolding aids, the filling procedure may be relatively slow with the mat only having a slightly defined position in the restraint position.
Furthermore, a side impact protection device for vehicle occupants is known (DE 196 45 031 A1) in which in the event of a side impact an unfoldable protective curtain is merely pulled from above over the region of the vehicle window. For this purpose, a vertical rail guide is provided in which a projectile connected to a side corner of the protective curtain can be moved downwards with the aid of a gas generator. This protective curtain does not contain any inflatable restraint cushions and so the protective effect is relatively mall as compared with air-bag devices.
The object df the invention is to provide an air-bag device which has a very rapid inflating procedure with good occupant protection and low aggressiveness, in particular when xe2x80x9cout of positionxe2x80x9d.
According to the present invention at least one of the restraint cushions is designed as a distributor cushion which is the first of the plurality of restraint cushions to be subjected to a gas mass flow from the gas generator. In the restraint position the distributor cushion at least partially covers an assigned vertical pillar. In addition, the distributor cushion has discharge openings through which portions of the gas mass flow from the gas generator can be supplied to the other restraint cushions, optionally via filling channels. The restraint cushions can be designed as air-bag chambers of an air bag of single- or multi-part design.
By means of the design of a distributor cushion which is the first to be subjected to a gas mass flow from the gas generator and which is inflated in front of a vertical pillar, there is advantageously already effective impact protection with respect to a vertical pillar shortly after the inflating procedure has begun. Only a relatively small gas mass flow is required in order to inflate the distributor cushion and thus the distributor cushion can be inflated very rapidly. No aggressiveness with respect to a vehicle occupant is to be expected from the inflating procedure of the distributor cushion in the region of the vertical pillar. Since the distributor cushion is inflated very rapidly and the inflating procedure for the other restraint cushions takes place via a plurality of discharge openings of the distributor cushion, suitable dimensioning of the discharge openings with respect to the arrangement and the diameter can also result in a very rapid inflation of the protective wall for the entire air-bag device. In conjunction with the dimensioning of the discharge openings and of the filling channels, specific influencing of the time sequence and of the inflating volume of the other restraint cushions is possible, which makes possible adaptation to vehicle-specific and individual conditions.
For a specific distribution of the gas mass flow, the distributor cushion may also consist of chambers or gas channels. Furthermore, the filling procedure and/or the service lives of the restraint cushions may, depending on the requirements, optionally be influenced by panels and/or gas diverters and/or nonreturn valves.
In the event of a vehicle overturning, both air-bag devices on both sides of the vehicle are expediently triggered. In addition, use can be made of stepped generators which are known per se and with which gas can subsequently be blown into the restraint cushions in order to extend the service life and/or in the event of a multiple collision.
As a stable part, the gas generator is to be arranged outside a potential head-impact region of front and rear occupants of the vehicle, preferably in a lateral roof strut in the vicinity of the B-pillar. Depending on the specific conditions, an arrangement of the gas generator in the vertical pillars, in the boot or in the engine compartment may also be expedient.
To give specific and rapid filling of the restraint cushions, it is proposed to connect at least one filling channel which is connected to the restraint cushions to the discharge openings of the gas distributor cushion.
In a particularly advantageous arrangement, in the restraint position the gas distributor cushion covers the B-pillar, it then being possible, depending on the embodiment in each case, to provide at least one inflatable filling channel in the direction of an A-pillar and/or at least one inflatable filling channel in the direction of a C-pillar and/or D-pillar. By this means, in conjunction with a rapid inflating procedure, extensive covering of a possible head-impact region on the vehicle side wall can be carried out.
In the restraint position an upper filing channel is to be provided in a fixed position in the region of a lateral roof longitudinal member and a lower filling channel is to lie somewhat above the window parapet. A simple and rapidly fillable arrangement is achieved if the upper filling channel and the lower filling channel are connected at their ends to form an annular channel, and the restraint cushions can be filled in their position on the respective annular-channel region by the annular channel through corresponding discharge openings. The restraint cushions are then expediently rapidly inflated from the roof lining and/or from the window parapet by corresponding lower and upper filling channels via the annular channel.
In order to protect front and rear occupants, starting from a gas distributor cushion in the region of the B-pillar, front and rear filling-channel and annular-channel arrangements having assigned restraint cushions are used. During inflation of the gas distributor cushion the lower filling channels and lower regions of the annular channels are then moved downwards in the direction of the window parapet. In a preferred embodiment, the restraint cushions are then filled both from above and from below via the upper and lower filling channels and parts of the annular channels.
As a result of the restraint cushions (when the restraint cushions have not yet been inflated or are only partially inflated, as a result of their fabric material), right at the beginning of the inflating phase, a curtain is extended from the roof lining or the roof paneling as deflection protection, for example against broken glass in the event of overturning.
With appropriate dimensioning of the size ratios of the components, in particular of cross-sectional ratios of the filling channels and/or discharge openings, time sequences during the inflating procedure of the restraint cushions can be influenced and predetermined. For this purpose, the at least one filling channel or annular-channel section which is assigned to the A-pillar advantageously has a larger cross section than the at least one filling channel or annular-channel section assigned to the C- and/or D-pillar. This has the effect that the front restraint cushions for the front occupants are filled more rapidly than the restraint cushions for the rear occupants, since the rear seats for rear occupants are, in statistical terms, only infrequently occupied.
In an advantageous further embodiments, it is proposed for the distributor cushion and/or the filling channels to be assigned a valve arrangement which can be used to control individual or groups of discharge openings with respect to the gas mass flow. In this arrangement, the valves can be controlled electrically or pneumatically. However, valve control preferably takes place automatically by means of the gas mass flow, optionally in conjunction with gas mass counterflows.
With appropriate valve controls, at the beginning of the inflating procedure the main gas mass flow, for example, can then be directed into the restraint cushions for the front occupants. If, using means which are known per se, it is recognized that a seat is occupied, an appropriately controlled valve in the distributor cushion, for example when rear seats are not occupied, can deflect the gas mass flow only to the restraint cushions for the front occupants and the restraint cushions for the rear occupants are not filled.
In principle, the protective wall is unfolded during the inflating procedure by the gas mass flow directed into the distributor cushion, the filling channels and the restraint cushions. In order to accelerate the unfolding and positioning of the distributor cushion, use can additionally be made of a drive assembly which is connected to the distributor cushion via a tensile element. In this arrangement, use can advantageously be made, in a manner known per se, of a pyrotechnically operated pretensioning device, optionally in conjunction with a seat-belt pretensioning device. As the tensile element, a cable requiring little installation space can be integrated in a side paneling, for example on the rear side of a pillar. With an arrangement of this type, the unfolding of the protective wall can advantageously be accelerated and an opening fright for an affected occupant as well as loading in an xe2x80x9cout of positionxe2x80x9d case can be reduced.
The elements of the air-bag device can be integrated all together or partially in paneling parts or a roof inside lining and/or can be preassembled thereon, as a result of which favorable installation costs in the case of a small installation space are obtained. In this arrangement, the gas channels are produced from the cushion fabric, which enables a reduction on installation space and weight as compared with known gas lances made of steel or plastic. Valve arrangements also advantageously contribute to this because of the sewn-in valve flaps.